Need a specific sensor that will detect when a pet comes close in a range of distance. As it comes close a beep intimates that the pet has reached. What sensor will work here. Can it work with an Arduino. ?
cat has a habit of going down 2 floors to poop. Problem is when she comes back the door is closed and neighbours don't like it. So a system by which moment she comes within a certain distance of a gadget it then beeps. May be a product already in market. Or if need be to put things together to work. Bell is a good idea but won't be loud.